DE3303590A1 - Electromotively driven window lifter having a safety circuit - Google Patents

Abstract

What is described is an electromotively driven window lifter which contains a safety circuit against the pinching of fingers and the like during the window-closing movement. The safety circuit comprises a data memory, in which the power/path diagram of an undisturbed window-closing movement cycle is stored. The circuit also contains means which determine the instantaneous power requirement in the initial phase of each closing movement. By means of these data, the stored power/path diagram is corrected in a computing unit. This power/path diagram is assigned a preset tolerance, and the computing unit is programmed in such a way that the drive motor is stopped or its polarity reversed when the power exceeds the tolerance limit, the tolerance limit being set so high for the last phase of the path that the power increase caused by the butting of the pane against the upper window frame causes no reversal of polarity of the motor.

Description

Electric motor-driven window lifters

with a safety circuit The invention relates to Electric motor-driven window regulators for automobiles and similar vehicles with a safety circuit.

Such window lifters can be of the known scissor type window lifters be, but it can also be modern Bowden cable window lifters, in which the window pane is moved by means of a closed loop of rope, with the rope in one place is wound around a cable drum driven by an electric motor will.

These electric motor driven window lifters are closed by closing a switch on the dashboard or the like in motion and have the disadvantage that the upward movement of the window pane has the hand, the head etc. of an uninvolved person can become trapped if the window is closed carelessly. Safety circuits have therefore already been proposed to overcome this disadvantage to avoid. The function of these safety circuits is designed in such a way that the disc reverses its direction of movement if it moves upwards encounters resistance.

If there is such a resistance in the disc path, it decreases the motor driving the window regulator momentarily has an increased current, and it is has already been proposed in DE-OS 26 10 558, with this increased current or to control several relays, which reverse the direction of current flow on the drive motor and thereby causing the window pane to move downward.

However, these and similar circuits all have various disadvantages: First of all, they have the disadvantage that they need a special switch to the safety circuit shortly before the target stops at the top Turn off the window frame. This is necessary because also when the disc hits up against the frame the current consumption of the motor increases and the safety circuit would make to respond. The result would be that the window would never close because every time the motor switches over at the top stop and itself the disk would move down again.

The main disadvantage of the known circuits, however, is that they have no regard for what is required for normal disk movement Take motive power. This force required for normal disc movement, and thus the power to be demanded from the engine is not constant, but rather extremely variable. The power currently required depends, for example, on whether it is a new or an older automobile. In the former case the rubber and twill seals are still firmly on the window and so is the window regulator gear is even more difficult to move. As a result, even during normal operation, a larger Motor power required to move the disc. In an older car seals and gears are smoother, so that a comparatively smaller one Motor power is sufficient to move the disc.

The normal power requirement is, however, especially higher when the window lifter is operated in winter, because then the window occasionally freezes, the rubber seals are not as flexible, and for this reason the washer already is is so stiff in normal operation that the engine does so much in normal operation Current absorbs that the relay circuit is triggered by this alone. this has as a result, the window cannot be moved up at all.

The invention is based on these disadvantages. to overcome and to specify a safety circuit of the type mentioned, which also works with changing normal motor power requirement on the one hand closes the window reliably, on the other hand but also take account of changing normal power requirements in their safety function wearing.

This task is the case with an electric motor-driven window lifter solved, which has the features specified in the claims.

The features essentially consist of a pulse generator, a Power meter, a data memory and an electronic arithmetic unit with connected program memory and connected switching means for motor switching. The pulse generator is attached to the transmission of the window regulator and is used e.g. count the number of revolutions of the motor shaft. These impulses thus provide information about the direction of movement of the disc and about their respective position between their lower and upper limit position.

The power meter is used to measure the power consumption of the motor during to measure the disc movement, taking the measurement during the initial phase of the closing movement or the opening movement is of particular importance, as will be explained will.

In the data memory, the performance-Weo diagram is undisturbed the closing movement in progress.

The arithmetic unit is used in accordance with the in the program memory registered program with the measurement data delivered by the power meter correct the power-distance diagram contained in the data memory.

In addition, a tolerance is entered in the arithmetic unit to reduce the the power-distance diagram of the current movement of the - possibly corrected - stored power-distance diagram may deviate. If this tolerance is exceeded, switching means connected to it are activated by the arithmetic unit and which either reverse the direction of current flow on the motor, i.e. reverse the polarity of the motor, or interrupt the flow of current to the motor at all. This tolerance will always be exceeded if there is a resistance in the path of the disc, e.g. a pinched one Hand or the like, and thereby the power consumption of the motor increases.

For the last phase of the closing movement, which is triggered by the pulse generator is established, this tolerance is increased to such an extent that even when striking the window pane on the upper pane frame does not exceed the tolerance limit will. There is accordingly no polarity reversal at the upper stop of the window pane of the motor. This practical deactivation of the safety circuit happens without that an additional switch would be required for this.

In addition, a special switch is connected to the processing unit, with which the tolerance specification can optionally be switched off entirely. An operation this special switch causes the disc to move throughout its travel is shifted with the maximum available power consumption.

In the drawing, the invention is shown in one embodiment. Show it: 1 schematically shows a circuit diagram of the drive motor a window lifter with the invented safety circuit, -Fig. 2 schematically the power-path diagram of an undisturbed window closing movement stored in the data memory.

In Fig. 1, 1 is the drive motor of an otherwise not shown Called window regulator. The motor 1 is powered by a power source 2 of for example 12 V voltage is supplied, and it is switched on via a switch la, so that depending on the polarity, it rotates in one or the other direction of rotation (upwards and downward movement of the disc).

A power meter 3 is connected to the supply line to motor 1, which measures the voltage at 3a and the current flow at 3b.

Further components of the circuit are a data memory 4 and a Computing unit 5 with connected program memory 6. The power meter 3, the Data memory 4 and the computing unit 5 are via a voltage stabilizer 7 supplied with voltage. A single-chip microcomputer, for example, can be used as the arithmetic unit 5 of the type 8748 as commercially available from various companies will.

A memory of the known type PROM can serve as the program memory.

On the engine 1, a pulse generator 8 is attached, which is one of the number of Motor shaft revolutions provides a proportional number of pulses and thus a Information about the direction of movement and the current position of the disc between their limits. An inductive proximity switch, for example, can be used as such a pulse counter. a Hall effect switch or a light barrier can be used.

The information determined with the named blocks, i.e. the Pulses from the rotation of the motor shaft and the instantaneous motor power are given e.g. when the window is closed via the arithmetic unit 5 into the data memory 4 given and in this a power-path diagram for an undisturbed process the closing movement saved.

Such a diagram is shown in FIG. Is on the abscissa the path is plotted, the engine power (approximately I.U) is recorded on the ordinate.

The diagram shows that after a start-up performance in the initial phase approximately constant power is required to move the disk move. But should the pane be based on the design of the pane guide, so to speak by default, e.g.

be more difficult to move than in the lower range of motion, the power curve shown here horizontally would be not be a straight line but a rising curve.

At the end of the path, the performance curve naturally rises sharply, because here the pane moves into the upper pane frame and is in its movement stopped.

The program written in the program memory provides that after Decay of the increased power required to start the target on a relative short distance "A" a reference measurement of the power is carried out and this reference measurement compared in the computing unit 5 with the power stored in the data memory 4 will.

However, this reference measurement does not necessarily have to occur during the closing movement of the window, but it can just as easily be done with the previous one The opening movement of the window must have taken place. It is also conceivable to use this reference measurement mixed, i.e. to be carried out during the opening and closing movement.

Depending on the result of this comparison, the entire data is stored in the data memory saved power-distance diagram corrected, i.e. shifted parallel to itself, as indicated by the dashed curve 9. The result is the reference measurement E.g. that normal disk movement requires 1 watt more power is, this can only result from the fact that the disk is over due to external influences the entire route is more difficult. Of course, the reverse is also possible occur that the disk can be moved more easily, e.g. because of Wear of the disc seals, etc. In any case, the stored power-displacement diagram adjusted according to the external conditions ".

This power-path diagram is now in the arithmetic unit 5 Assigned performance tolerance limit. The performance can increase within this limit, without the arithmetic unit showing any effect.

However, uniswitches 10-13 are still connected to the arithmetic unit, which are shown in Fig.1 as relays, but in practice they are better than contactless ones Switches, e.g. designed as MOSFET transistors. If the engine power exceeds the specified tolerance limit, i.e. dips in the path of the window pane at its Closing movement on a resistance, the arithmetic unit activates this switch and reverses the polarity of the motor. The disc then moves down again and releases the jammed one Hand or the like free. It depends on the program written and saved whether the disc runs back over its entire displacement path, or whether after one predetermined return distance the motor is stopped. The latter would be useful in order to prevent someone from outside with criminal intentions from getting into the window closing movement intervenes, through the response of the safety circuit and the return of the target allows free access to the interior of the car through the fully open window will.

If desired, the program can also be written in such a way that when the power tolerance limit is exceeded, the engine is simply switched off will.

It has already been mentioned that when the disk runs in against the upper Window frame and the resulting increase in engine power, the safety circuit may not respond, and that for this purpose in the previously known safety circuits a special switch must be provided, which the safety circuit approx. 5-10 mm before the upper edge of the window enters the upper window frame.

With the invented window regulator, this particular switch is used in simply avoided by the fact that for this last distance-established by the pulse generator - a very high tolerance limit is specified, which is practical cannot be exceeded.

As a result, the safety circuit is made ineffective without a special switch would be required for this.

But since occasionally there may be a need to open the windows To close in one go with maximum engine power is with the arithmetic unit 5 another switch 14 is connected. When this switch 14 is actuated, the tolerance specification switched off over the entire distance, so that the disc with the entire to Available engine power is closed.

With the mentioned electronic components in the circuit shown the following is realized: The power-distance diagram of a normal The closing movement sequence is saved. This normal graph is a performance tolerance limit assigned. If the power exceeds this tolerance limit, the polarity of the motor is reversed.

The power-distance diagram is not constant, but is shown in corrected its position, based on the performance that occurred during the initial phase every closing movement is determined by the power meter 3. There is still tolerance received in the intended amount.

It appears graphically as a parallel to the power-distance diagram Curve 15 (Fig.2), which, together with the power-path diagram, is parallel to itself itself is moved. The curve of the tolerance limit runs on the last stretch of the route however not never parallel to the power-distance diagram, but the limit becomes Set much higher to prevent the motor from reversing its polarity when the disc hits the stop to prevent in the upper pane frame.

In the same way as above with regard to the closing movement the window pane, a power path diagram can also be used for the Opening movement of the disc are stored in the data memory 6 and by a Reference measurement at the beginning of the opening movement of the pane corrected in its data will.

A performance tolerance limit could also be specified for this diagram be. But since less is to be expected with the downward movement of the window pane, that a hindrance to movement occurs, this case is not explained in more detail. Suffice it to say that all measures necessary for the closing movement the window pane are provided in an analogous manner for the opening movement can be provided.

Claims (3)

Claims S Electric motor-driven window lifters for automobiles and l similar vehicles with a safety circuit through which the dependency from increased engine power with one of the normal resistance to movement of the Window pane momentarily rising resistance during the closing movement the window pane reverses or interrupts the direction of current flow at the drive motor is characterized by the following features: a is in the transmission of the window regulator contain a pulse generator (8) which is proportional to the number of revolutions of the motor shaft Number of pulses provides information about the direction of the disc movement and the current position of the pane between its lower and upper limit position there, b the window regulator contains an electronic power meter (3) for constant Measurement of the power consumption of the drive motor (1), c contains the window regulator a data memory (4) for storing the last power-distance diagram undisturbed sequence of a window closing movement, d the window regulator contains a Computing unit (5) with an attached program memory (6), which constantly the Measurement data from the pulse generator (8) and those from the power meter (3) are supplied , and based on the program stored in the program memory (6) the in the data memory (4) stored power-distance diagram in its position accordingly the measurement data corrected the currently running window movement, A performance tolerance limit is assigned to the performance-travel diagram and includes the arithmetic unit (5) are connected to switching means (10-13) which, when a the power exceeding the specified tolerance is activated by the arithmetic unit (5) and reverse or interrupt the direction of current flow at the motor (1), and f for the final phase of the closing movement, the power-travel diagram is so high Tolerance limit assigned that even with complete stopping of the closing movement the switching means (10-13) are not activated. 2.) Electric motor-driven window lifter according to claim 1, characterized characterized in that a special switch (14) is connected to the computing unit (5) is, when actuated, the tolerance specification can optionally be switched off. 3.) Electric motor-driven window lifter according to claim 1, characterized characterized in that the program for the arithmetic unit (5) is written in the manner is that the drive motor (1) after activation of the switching means (10-13) after a predetermined return path of the disc is switched off.